1. Field of the Invention
The present invention relates to an optical connector.
2. Description of the Prior Art
Various optical connectors have been used for connection or changeover of optical fibers.
For instance, in FIG. 13, there is shown a first optical connector 1 which comprises a rectangular-parallelpiped ferrule 2 having a butt end face 2a at the front portion of the ferrule 2 and positioning pin holes 2b, 2b formed at the opposite sides in a widthwise direction of the ferrule 2, and a fiber ribbon 3 having a plurality of optical fibers 3a, mounted to an rear portion of the ferrule 2. These pin poles 2b and respective optical fibers 3a are arranged in parallel with each other so that they are perpendicular to the butt end face 2a.
In the case where the optical connector 1 is abutted against an another optical connector 1 so as to make an optical communication line connection, a refractive index matching agent is applied on the butt end face 2a so as to prevent a light from being reflected backward, and these optical connectors 1 are abutted against each other by interposing positioning guide pins between pin holes 2b, 2b of the connectors opposed to each other.
Moreover, in order to prevent the foregoing reflection of light from occurring in the butt end face without using the refractive index matching agent, a second optical connector has been used. To give an example of the second optical connector, in FIG. 14, there is shown an optical connector 4 having a butt end face which is inclined with respect to an optical axis of an optical fiber. In an optical connector 4 shown in FIG. 14A, a butt end face 5a at the front portion of a ferrule 5 is formed so that the lower portion of the butt end face 5a is inclined backward by an angle of .theta..sub.1 with respect to a vertical direction. On the other hand, in an optical connector 4 shown in FIG. 14B, the butt end face 5a at the front portion of the ferrule 5 is formed so that a left-hand side of the butt end face 5a is inclined backward by an angle of .theta..sub.2. As described above, the respective butt end faces 5a are inclined with respect to the optical axis of each optical fiber 6a to prevent an end reflection from occurring in the butt end face. In both optical connectors 4, pin holes 5b and respective optical fibers 6a of a ribbon fiber 6 are arranged in parallel with each other, like the optical connector 1.
Also, Unexamined Japanese Patent Publication (KOKAI) No. 58-152212 discloses a third optical connector which can prevent a reflection of light from occurring in an butt end face without using a refractive index matching agent. In that optical connector, an end reflection is prevented from occurring by inclining optical fibers in only the vicinity of the butt end face.
However, the foregoing first optical connector requires wiping off or applying the refractive index matching agent on the butt end face every time that the first optical connector is abutted against an another optical connector. For this reason, there has arisen a problem in that not only an abutting work is troublesome, but also the working place becomes dirty due to the refractive index matching agent.
Further, the foregoing second optical connector has a butt end face which is formed with an inclined plane; therefore, the butt end face is not parallel with a back end of the ferrule. For this reason, in the case where the second optical connector is abutted against an another connector, if a pressing force is applied to the abutting direction, a difference occurs in alignment between butt end faces of these optical connectors abutted against each other. As a consequence, great optical connection loss is caused.
Furthermore, the foregoing third optical connector is constituted so that optical fibers are inclined in only the vicinity of the butt end face. For this reason, there has arisen a problem in that the structure of this connector is complicated; therefore, it takes much time to manufacture such a connector, and such connector is expensive to manufacture.